ESD devices have been widely used in integrated circuits to prevent damages from electrostatic voltage. Generally, the ESD devices occupy substantial space in an integrated circuit, which increases the manufacturing cost. Furthermore, conventional ESD devices are generally located near the pads horizontally. The dimension of the ESD devices is generally large and the current flowing characteristic of the conducting wire, such as metal, is not ideal. This could causes that the current flowing through the ESD device is not average. Moreover, this may affect the electric character and reduce breakdown endurance of the ESD device.
Therefore, an ESD device with reduced essential space and improved electric character is desired.